Floor is a rounding primitive that reports the closest integer below the number, rounding down. For example, show floor 4.8 would return 4, and show floor -7.5 would return -8.
Ceiling is another rounding primitive that reports the closest integer above the number, rounding up. For example, show ceiling 5.3 would return 6, and show ceiling -4.4 would return -4.
Once you mastered the ceiling primitive, don't stop there. Check out the resources below to improve your NetLogo skills.
ceiling primitive: